Featured Research

from universities, journals, and other organizations

Hibernating Squirrels Provide Clues For Stroke, Parkinson's

Date:

November 5, 2002

Source:

Medical College Of Georgia

Summary:

A compound that enables squirrels to hibernate may one day help minimize brain damage that results from stroke, according to a researcher at the Medical College of Georgia and Veterans Affairs Medical Center in Augusta.

Share This

A compound that enables squirrels to hibernate may one day help minimize brain damage that results from stroke, according to a researcher at the Medical College of Georgia and Veterans Affairs Medical Center in Augusta.

Related Articles

In an animal model for stroke, delta opioid peptide reduced by as much as 75 percent the damage to the brain's striatum, the deeper region of the brain and a major target for strokes, according to Dr. Cesario V. Borlongan, neuroscientist.

In fact, evidence suggests that the compound, which puts cells in a temporary state of suspended animation, may help protect brain cells from the ravages of Parkinson's disease as well.

"When the animals were introduced to an experimental stroke, then injected with delta opioid peptide, we could see a reduction in the damage done by stroke; brain damage is reduced and the neurological deficits associated with stroke are definitely reduced," Dr. Borlongan said.

More extensive animal and human studies are needed but Dr. Borlongan said the peptide, which occurs naturally in man and may play a role in the body's effort to protect the brain, should one day minimize stroke damage.

His stroke work garnered the International College of Geriatrics Psychoneuropharmacology Award presented this month at the college's annual meeting in Barcelona, Spain.

The original insight about squirrels and delta opioid peptide came from work by Dr. Tsung-Ping Su at the National Institutes of Health. In the 1980s, Dr. Su was studying hibernation and found increased levels of the compound. Dr. Su also found that when he gave non-hibernating squirrels more of the compound, the previously hyperactive critters began hibernating even in the summer.

Although there's no hard evidence that humans hibernate, they do have endogenous levels of delta opioid peptide that Dr. Borlongan believes may play a role in natural protective mechanisms.

During hibernation, levels of the peptide increase and the metabolic rate and energy demands of the entire animal drop dramatically. That led Dr. Borlongan to wonder if that same state might help protect brain cells specifically. "Our thinking here is that if we take this drug, probably brain cells are going to go into this mode of hibernation. So if you get a stroke or some other neurological disorder, most of the brain cells will be protected."

When Dr. Borlongan gave high doses of the compound to the animal model for stroke, the rats - which are not known to hibernate - looked sleepy in the hours following but recovered dramatically. In fact, at least in rats, the levels of endogenous peptide increased immediately following a stroke, which makes him suspect that the levels may also increase in humans.

Patients who receive more of this compound in the hours after stroke - much as many now receive TPA or aspirin - may get significant protective benefits. "The oxygen needs were dramatically reduced: that is how it works to protect the brain," Dr. Borlongan said of the animal cells.

To study the role in Parkinson's, he put varying levels of delta opioid peptide into a culture containing dopaminergic cells, which produce dopamine, a key cell communicator deficient in Parkinson's. He found that those that got the most peptide survived the longest. In an animal model for the disease, the reduction in dopamine levels was far less in the animals receiving the highest doses of delta opioid peptide.

These findings, presented at the Barcelona meeting and reported partially in the journals NeuroReport and Cell Transplantation, point to the potential of the compound but also to the need for additional animal studies before moving toward clinical trials, Dr. Borlongan said.

One critical issue is that the animal model for stroke has only a single stroke and the majority of humans have a second stroke within months. One of his many goals is to develop a better animal model and see if compounds such as delta opioid peptide and TPA can help patients avoid subsequent strokes.

Other issues that need study are potential side effects, such as how well do the cells function after hibernation; animal models were sleepy while getting the drug but they functioned well afterward, he said. "My feeling is that sleep could be a correlate of hibernation."

The researcher believes this cell hibernation may have other roles as well, including slowing the aging process. Its potential for helping donated livers, hearts and kidneys remain viable longer until they are transplanted already is being explored by others in clinical trials.

Dr. Borlongan, who joined the MCG faculty in February after completing a senior staff fellowship at the NIH's National Institute on Drug Abuse, had NIH support for his work prior to joining the MCG faculty. He now has a VA Career Development Award. Several grant applications are pending.

This summer he also received the Rafaelsen Fellowship Award from Collegium Internationale NeuroPsychopharmacologicum in Montreal for his work in brain-cell protection strategies and neural transplantation. And, he was recently elected a councilor for the American Society for Neural Transplantation and Repair.

Story Source:

The above story is based on materials provided by Medical College Of Georgia. Note: Materials may be edited for content and length.

More From ScienceDaily

More Mind & Brain News

Featured Research

Mar. 3, 2015 — No significant change in home habits of smokers have been observed in the aftermath of a ban on smoking in public spaces, researchers report. Greater inspiration to kick the habit likely comes from ... full story

Mar. 3, 2015 — Heart function has been associated with the development of dementia and Alzheimer's disease through a new study. Participants with decreased heart function, measured by cardiac index, were two to ... full story

Mar. 3, 2015 — Children of recently separated or divorced families are likelier to drink sugar-sweetened beverages than children in families where the parents are married, putting them at higher risk for obesity ... full story

Mar. 3, 2015 — Although sedatives are often administered before surgery, a randomized trial finds that among patients undergoing elective surgery under general anesthesia, receiving the sedative lorazepam before ... full story

Mar. 3, 2015 — Why do people shake hands? A new study suggests one of the reasons for this ancient custom may be to check out each other's odors. Even if we are not consciously aware of this, handshaking may ... full story

Mar. 3, 2015 — It appears that stress markers in unemployed people can be found, independent of smoking, alcohol consumption and overweight/obesity. Results from a study suggest that long-term unemployment may be ... full story

Mar. 3, 2015 — On the heels of an American nationwide measles outbreak comes a report that campaigns aimed at scaring people about the consequences of non-vaccination might not be as effective as many think. ... full story

Mar. 3, 2015 — Doctors write millions of prescriptions a year for drugs to calm the behavior of people with Alzheimer’s disease and other types of dementia. But non-drug approaches actually work better, and carry ... full story

Mar. 3, 2015 — Briefly counseling college students on the dangers of binge drinking is effective in lowering heavy drinking levels among many students, but only temporarily. Three out of four will be right back ... full story

Mar. 3, 2015 — Loneliness brought about by the death of a spouse can trigger a wider network of depression-like symptoms, a study has found, but authors suggest that doctors are often too quick to attribute these ... full story

Related Stories

Jan. 5, 2015 — The circadian clock of arctic ground squirrels works differently during the cold of hibernation, new research shows. Many mammal species in colder climates spend the winter months in torpor, commonly ... full story

Sep. 4, 2013 — Fat-tailed dwarf lemurs are the only primates known to hibernate, and new research suggests their sleep patterns during hibernation are markedly different from those of ground squirrels, which also ... full story

May 2, 2013 — Until recently, the only primate known to hibernate as a survival strategy was a creature called the western fat-tailed dwarf lemur, a tropical tree-dweller from the African island of Madagascar. But ... full story

Sep. 15, 2011 — When Arctic ground squirrels are getting ready to hibernate they don't just get fat -- they pack on muscle at a rate that would make a bodybuilder jealous. And they do it without suffering the ... full story

July 26, 2011 — Hibernation is an essential survival strategy for some animals and scientists have long thought it could also hold promise for human survival. But how hibernation works is largely unknown. Scientists ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.